1. Field
Embodiments of the present invention generally relate to propylene-based polymers and films made therefrom. More particularly, embodiments of the present invention relate to films of propylene-based polymers having two or more additives blended therewith to improve mechanical and elastic properties.
2. Description of the Related Art
Materials with good stretchability and elasticity are used to manufacture a variety of disposable articles in addition to durable articles including incontinence pads, disposable diapers, training pants, clothing, undergarments, sports apparel, automotive trim, weather-stripping, gaskets, and furniture upholstery. For clothing, stretchability and elasticity are performance attributes that allow the materials to provide a closely conforming fit to the body of the wearer. Various types of elastic laminates have been used for such materials.
Elastic laminates, especially those used as diaper waist bands, leg cuffs, and elastic stretch engines, are intended to contact the wearer or user. As such, comfort is a primary design consideration. The comfort factor is a direct result of the stretchability and elasticity of the film; however, the stretchability and elasticity of the film usually comes with a price. As the stretchability and elasticity of the film increase, the films become less durable and more susceptible to tear. U.S. Patent Publication No. 2009/0105418 discloses hydrocarbon resins that can be added to the elastic material to increase tear resistance of a film without significantly compromising elastic properties. While enhanced tear strength is an important mechanical property of elastic films, it is only one of the mechanical properties important to the overall performance of elastic materials.
Accordingly, technology is available to increase the elasticity of a base elastic material while sacrificing mechanical properties. Additionally, technology is available to increase the mechanical properties of the base elastic material while sacrificing elastic properties. Still further, technology is available to increase the tear strength of an elastic material without compromising elastic properties. However, there is a continuing need for increasing more than one mechanical property without compromising the remaining physical and elastic properties.